benissimus wrote:I would recommend de caelo... rather than e caelo, since it has a sense of downward movement / motion originating from great heights.

I learned de as meaning "about or concerning"...Is they way I learned correct?

Yes, that is absolutely right, but literally it is an idea of motion down from (often "away from"). If you go down from a mountain, you DEscend (descendo, de+scando to climb down). This meaning was probably stretched to a more figurative prepositional meaning of "concerning".